The present invention relates to a bearing device to be used in a rotor type open end fine spinning machine or other high-speed rotary machines.
In a rotor type open end fine spinning machine in the prior art, a spinning rotor is rotated at a high speed greater thaan 40,000 r.p.m., since productivity of yarn is proportional to the revolution speed of the spinning rotor. A rotation shaft of the spinning rotor is supported by a ball bearing. A rolling-element bearing such as a ball bearing is provided with a plurality of rolling elements inserted between an inner race and an outer race to form a raceway and a retainer to hold constant spacing between the rolling elements.
If the revolution speed of the spinning rotor is increased to about 90,000 r.p.m., however, the rolling-element bearing may be damaged because of seizure or galling at the retainer. Since it is quite difficult that the rolling-element bearing in the prior art is rotated at a high speed more than 90,000 r.p.m., such a bearing cannot be said to be excellent in high-speed rotation performance.